WE'RE HEADED FOR AN EPIDEMIC OF JOINT DISEASE. WHAT YOU CAN DO TO PROTECT YOURSELF

The first sign is often a twinge in your knee or your back or some stiffness at the base of your thumb. Or maybe you're getting out of the car and a sharp pain shoots down your leg from your hip to your calf. "Nothing serious," you think. "I must have just strained something. I'm too young to have arthritis."

Think again. If you are within even shouting distance of middle age, chances are you have osteoarthritis, a degenerative disorder in which the cartilage--the natural shock absorber that cushions the insides of your joints--begins to break down. Doctors used to...